Alfred l



A. L SOHM.

ELECTRiCAL CONTROL MECHANISM.

APPLICATION FILED MAY 21. 1917.

mm fllfped L. doizm STATES PATENT orricn.

ALFRED L. SOHM, OF CHICAGO, ILLINOIS, ASSIGNOR TO SOHM ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

clean-concise, and exact description, reference being had to the accompanying drawings, forming a part of this specificatlon.

My invention relates to electrical control mechanism. More particularly it is con cerned with a system for controlling an electrical circuit whereby impulses are conducted at periodic intervals to a secondary clock circuit, or the like.

The object, of my invention is to provide improved and simplified means for theaccurate regulation and control of a circuit wherein are located one or more elements adapted to be. periodically actuated by means of impulses sent from a master con tact mechanism.

It is a further object of my invention to provide a master contact and control mechanism of improved construction .which is designed to lose and look a circuit for a certain interval of time whereby said circuit is maintained in a closed position until the end of said interval of time.

In the present invention I have shown the contact mechanism as controlling a circuit of secondary clocks, but it is to be understood that I do not limit my invention to use in such a system for it is obvious that the same is adapted for use in any number of instances where a plurality of devices are actuated by means of a common master control.

Heretofore in systems of the above class it has been found difficult to provide a reliable contact means which will' close and lock the control circuit which transmits periodic impulses to the secondary clock. A. great number of contact devices have been advanced which has proved faulty by reason of their failure to lock the control circuit after the same is once closed thereby rendering the clock system liable to receive more than a. single impulse for each certain time interval. This condition in a clock system is especially disastrous for it causes an inaccurate showing of time at the dials of the clocks.

- All these defects I have aimed to remedy Specification of Letters Patent.

Patented Dec. 2, 1919.

Application filed May 21, 1917. Serial No. 169,876.

in the present invention, an embodiment of which I have shown diagrammatically in the accompanying drawing.

The contact mechanism 1, I have shown as adapted to be secured to a master clock, of which only the minute hand shaft 2 appears 1n the drawing, it being obvious that other means for rotating the said shaft may be provided. A contact wheel 3 is fixed on the shaft 2 and comprises two adjacent segments, a metallic segment l and an insulating segment 5 which are secured together by means of the screws 6 to form the unitary wheel 3. About their periphery each segment is provided with flanges throu h which a grooved path 9 is formed on metal ic segment 4. and a similar rooved path 10 on insulating segment 5. The path 9 of segment 4 is not continuously metallic for the reason that a section of its periphery is cut away for the reception of the insulating section 11. Similarly the path 10 of segment 5 is not entirely of non-conductive material due to the insertion of the metallicsection 12 on it's periphery, which section 12 forms electrical connection withthe metallic segment 4. Contact arms 14L and 15 are disposed above the wheel 3 which are provided with the depending portions 16 and 17 adapted to make a continuous wiping contact with the paths 9 and 10, respectively, of the rotatable wheel 3. The arms 1 1 and 15 are of similar design and at one end are pivoted together and to any suitable means of support by means of the screw 18. Rings 19 are provided for insulating the arms from each other and from the screw 18. By extending the free ends 20 and 21 of the arms 14 and 15 beyond the axis of the shaft 2, a cantaliver action is obtained which tends to maintain the contact points 16 and 17 in firm communication with paths 9 and 10 of the wheel 3. Just enough weight is put intothe ends 20 and 21 to cause this firm contact without in any man ner hinderinlg the proper rotation of the shaft :2. The arms 14: and 15 are provided with the binding posts 22, 23, to which connection is made with the outside circuit, as follows:

From the post 22 is led a conductor 24: which connects with an armature 25 of a lock-up relay 26 and thence through the spring contact 27 and the conductor 28 to one side of the battery 29. The circuit is completed from the other side of the battery by the conductor 30 to the relay 26 and thence by the conductor 27 through the wheel 3 and the arm 14. From the arm 15 the circuit leads from the post 23 through the conductor 31 to one side of the battery 29, and thence through the common wire 30, the relay 26 and the common wire 27 through the wheel 3 to the arm 15. The working circuit, which in this case is a secondary clock circuit, is connected from the common wire 30 by the conductor 32 to a second armature 33 of the lock-up relay 26, thence through the spring contact 34 and the conductor 35 which forms one side of the clock circuit. Conductor 36 forms the other side of the clock circuit and is connected to the o posite side of battery 29 through the con uctor 31. Any number of secondary clocks 40 may be inserted in multiple between the conductors 35 and 36. A switch 41 may be inserted in the common wire 27 for manually disconnecting the timing device and the working circuit. The

operation of the device is as follows:

As the wheel 3 rotates on the minute hand shaft 2 the circuit will be normally open until the point 12 of the insulatin segment 5 makes contact with the tip 17 0% the contact arm 15, at which time the circuit will be closed through the conductor 31, battery 29, conductor 30, through the lock-up relay 26 and the,common wire 27 and the wheel 3. The relay 26 is thus energized causing its armatures, 25 and 33 to make contact with the springs 27 and 34, respectively. It is 10 be noted that at this time the contact ,point 16 of the arm 14 makes connection with a metallic portion of the path 9 of'the segment 4 and therefore when the relay 26 is energized, the locking circuit is closed through the arm 14, conductor 24 contact 27, conductor 28 through the battery 29, relay 26 through the metallic segment 4. At the same time the secondary clock circuit is closed through the contact 34, conductor 35, conductor 36, through conductor 31, battery 29 and conductor 32, and an impulse of current is thereby sent through the secondary clock circuit. It now becomesevident that once contact is made between the arm 15 and the oint 12 on the segment 5, the circuit is e ectively locked in a closed condition through the arm 14, and it is immaterial what the subsequent action of the arm 15 mayv be for the circuit will remain locked through the arm 14 as long as its part 16 makes contact with the metallic portion of the segment 4. As the wheel 3 continues to rotate the point 17 of the arm 15 soon is passed by the conducting portion 12 of the segment 5, whereupon the point 17 makes contact with the insulated portion of the segment 5, which action causes a breaking of the circuit through a conductor 31, battery 29 and the Wheel 3 but the relay 26 continues to be energized throu h the arm 14 and the locking circuit, as above explained, whereby the secondary clock circuit is also maintained in a closed condition. As the wheel 3 continues to rotate the point 16 of the arm 14 presently strikes tli insulated p'o'r'ti n 11 of the segment 4 and not until this me is the locking circuit opened. When this action takes place the relay 26 is denergized and the locking circuit is open at he contact- 27 and the secondary circuit at the contact 34 and it is apparent that the circuit can not again be closed until the wheel 3 has made a complete revolution and the point 12 again contacts with the point 17 of the arm 15. The wheel 3 makes one revolution per minute and in this manner the secondary clocks receive one impulse of current each minute and are effectively prevented from receiving more than one impulse per minute so that anaccurate showing of time at the secondary clock is assured.

It is not my intention to limit myself to the specific embodiment of my invention above described, but to include as coming within the scope of my invention those changes and modifications which will be suggested to'those skilled in the art.

What I claim is:

1. In a system of the class described, a timing element comprising a conducting disk and a non-conducting disk, relatively stationary wipers contacting with said disks, said conducting disk carrying a non-conducting segment, said non-conducting disk carrying a conducting segment, a relay circuit adapted to be closed through said conducting segment and to be opened by said non-conducting segment, and a working circuit maintained closed by the relay while energized.

2. In a system of the class described, a. rotatable element comprising a conducting disk and a non-conducting disk, a non-continuous conducting area on said conducting disk, a non-continuous insulating area on said non-conducting disk, wipers for said areas on said disks, a relay circuit, a normally open working circuit adapted to be maintained closed by the relay when energized, the contiguous ends of said conducting and non-conducting areas being spaced apart on the periphery of said element to maintain the relay circuit closed a predetermined time interval.

3. A rotatable timing disk having a conducting periphery sald periphery interrupted at one point by a section of insulation material, a peripheral contact projecting laterally from said disk, a wiper for said disk, a second wiper adapted to contact with said projection upon each revolution of the disk, a relay circuit including said disk and its wiper, an auxiliary circuit including the relay, said disk and the second Wiper, the said projection and insulation sections being circumferentially separated, a said projection adapted to close the relay circuit and the insulation section being adapted to open said relay circuit after a predetermined interval of time.

4. In a system of the class described, a normally-open locking circuit, a normallyopen working circuit, a plurality of devices to be actuated in said working circuit, a relay, a timing element adapted to move at a uniform velocity, a metallic path on said timing element having a relatively small portion of insulating material thereon, an insulated path on said timing element having a relatively small ortion of conducting material thereon, an angularly displaced from said small portion of insulation, continuous wiping contacts on said paths, said relay adapted to be energized during the angular movement of said timing element from said small conducting portion to said small insulating portion to maintain the Working circuit closed.

5. In a system of the class described, a normally-open locking circuit, a normallyopen working circuit, a plurality of devices to be actuated in said working circuit, a relay, a timing element adapted to rotate in a given period of time, a metallic path about the periphery of said timing element, broken at one point 'by arelatively-small portion of insulation, an insulated path about the periphe of said timing element broken at one point by a relatively small portion of conducting material, said two small portions being disposed at non-adjacent points on the periphery of said timing element, contact arms on said paths whereby said working circuit is maintained in a closed condition during the rotation of said wheel from the cooperation of one of said contact arms with on, continuous wiping-contacts on said paths whereby said working circuit is closed during the angular displacement of said timing element from said small conducting portion to said small insulating portion once during a single rotation of said timing element.

7. In a system. of the class described, a circuit-changing rotatable element comprising a disk composed mainly of conducting material, and a disk composed mainly of insulating material, a small insulating portion on said first disk, a small conducting portion on said second disk, wipers on said disks, a relay, a working circuit, a plurality of devices to be actuated in said working circuit, a circuit adapted to be closed during the cooperation of one of said wipers with said small conducting portion, thereby energizing said relay, a separate circuit adapted to be closed by the energization of said relay, said working circuit also being closed by the energization of said relay, said separate circuit, and thereby said working circuit, being adapted to remain closed until the cooperation of the second of said wipers and said small insulating portion.

In Witness whereof, I hereunto subscribe my name this 17 day of May A. D. 1917. ALFRED L. SOHM. 

